The present invention relates to compounds and their uses, and in particular to compounds which have a mimetic or antagonistic property of an inositol phosphoglycan, and the uses of these compounds, e.g. to treat a condition ameliorated by administration of an IPG second messenger or an IPG antagonist thereof.
Many of the actions of growth factors on cells are thought to be mediated by a family of inositol phosphoglycan (IPG) second messengers [13]. It is thought that the source of IPGs is a xe2x80x9cfreexe2x80x9d form of glycosyl phosphatidylinositol (GPI) situated in cell membranes. IPGs are thought to be released by the action of phosphatidylinositol-specific phospholipases following binding of growth factors to receptors on the cell surface. There is evidence that IPGs mediate the action of a large number of growth factors including insulin, nerve growth factor, hepatocyte growth factor, insulin-like growth factor I (IGF-I), fibroblast growth factor, transforming growth factor xcex2, the action of IL-2 on B-cells and T-cells, ACTH signalling of adrenocortical cells, IgE, FSH and hCG stimulation of granulosa cells, thyrotropin stimulation of thyroid cells, cell proliferation in the early developing ear and rat mammary gland.
Partially characterised inositolphosphoglycans (IPGs) have been postulated to mediate the action of a number of growth factors including insulin and insulin-like growth factor I (IGF-I) [1]. Despite their isolation from several tissues type, the precise chemical structures of these IPGs are, however, still unknown and two main structural groups have been proposed on the basis of the chemical composition [2,3] which display different biological activity and tissue distribution [4]; the family of glucosamine-myo-inositol containing IPGs (IPG-A) and the family of chiro-inositol-galactosamine containing IPcs (IPG-P).
In an attempt to establish the minimal structural requirements for biological activity, a number of compounds containing some of the basic structural motifs that have been postulated for IPG mediators have been synthesised in the art [5]. These synthetic compounds include O-(2-amino-2-deoxy-D-glucopyranosyl)-xcex1(1xe2x86x926)-chiro-inositol 1-phosphate and O-(2-amino-2-deoxy-D-glucopyranosyl)-xcex1(1xe2x86x926)-myo-inositol 1-phosphate [6].
U.S. Pat. No. 6,004,938 (Hoechst) discloses a group of synthetic inositol glycans having insulin-like action. The compounds are based on 2-6 monsaccharide units linked to an inositol moiety. The examples in the patent all employ myo-inositol and are composed of 5 or 6 units apart from two pseudo-trisaccharide compounds G and H. Compounds G and H are HO-PO(H)O-6Man-xcex1(1xe2x86x924)-GluN-xcex1(1xe2x86x926)-(L)inositol-1,2(cyclic) phosphate and HO-PO(H)O-6Man-xcex1(1xe2x86x924)-GluN-xcex1(1xe2x86x926)-(L)inositol, otherwise known as O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-ammonio-2-deoxy-xcex1-D-glucopyranosyl)-(1xe2x86x926)-L-myo-inositol-1,2-cyclic phosphate and O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-amino-2-deoxy-xcex1-D-glucopyzanosyl)-L-myo-inositol. The properties of exemplified compounds are investigated in lipogenesis and glucose transport assays employing rat fat cells.
WO96/14075 (University of Virginia) discloses a generic family of compounds D-hexosamines linked to an inositol via a xcex21,4-linkage. The inositols can be myo or chiro-inositol or pinitol, while the hexosamines are glucosamine or galactosamine. However, this application describes the synthesis of just two compounds 4-O-(2-deoxy-2-amino-xcex2-D-galactopyranosyl)-D-pinitol and 4-O-(2-deoxy-2-amino-xcex2-D-galactopyranosyl)-D-chiro-inositol, or in JUPAC notation O-(2-amino-2-deoxy-xcex2-D-galactopyranosyl)-(1xe2x86x924)-D-pinitol and O-(2-amino-2-deoxy-xcex2-D-galactopyranosyl)-(1xe2x86x924)-D-chiro-inositol.
WO99/06421 (University of Virginia) describes synthetic insulin mimetic substances and includes a general formula I showing xcex21,4-linked disaccharides. However, despite this the compounds synthesised in this application are exactly the same as those disclosed in the applicant""s earlier application, WO96/14075.
A multi-step synthesis of a IPG-P mimetic from glucose has been previously reported in Jaramillo et al [6], which discloses a compound called C4, 1-D-6-O-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-chiro-inositol 1-phosphate. A further synthesis of C4 is described in our co-pending International Patent Application PCT/GB99/03715 (Rademacher Group Limited). Zapata et al [16] discloses three other compounds C1-C3 which are:
C1 1-D-4-O-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-myo-inositol 1-phosphate.
C2 1-D-6-O-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-myo-inositol 1-phosphate.
C3 1-D-6-O-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-myo-inositol 1,2 cyclic-phosphate.
It remains a significant problem in the art to produce synthetic compounds which can mimic one or more of the activities of inositol phosphoglycans or which act as antagonists of IPGs.
Broadly, the present invention relates to IPG mimetic and antagonist compounds and to methods of producing the compounds and to their medical uses. The compounds disclosed herein are useful as synthetic mimetics of IPG-P or IPG-A second messengers and/or growth factors whose action is mediated by IPGs, or a competitive antagonists of IPGs. In particular, the compounds are based on the 1,6 linkage of two or more sugar residues to a cyclitol.
Accordingly, in a first aspect, the present invention provides a compound represented by the general formula:
Yxe2x80x94Xxe2x80x941,6-cyclitol
wherein:
X represents a sugar radical;
Y represents one to three sugar radicals;
the sugar radicals and cyclitol are individually unsubstituted or substituted with between one and four groups independently selected from:
(a) phosphoryl groups such as phosphate xe2x80x94Oxe2x80x94P(O)(OH)2; thiophosphate xe2x80x94Oxe2x80x94P(S)(OH)2; phosphate esters xe2x80x94Oxe2x80x94P(O)(OR)2; thiophosphate esters xe2x80x94Oxe2x80x94P(S)(OR)2; phosphonate xe2x80x94Oxe2x80x94P(O)OHR; thiophosphonate xe2x80x94Oxe2x80x94P(S)OHR; substituted phosphonate xe2x80x94Oxe2x80x94P(O)OR1R2; substituted thiophosphonate xe2x80x94Oxe2x80x94P(S)OR1R2; xe2x80x94Oxe2x80x94P(S)(OH)(SH); cyclic phosphate;
(b) other phosphorus containing compounds such as phosphoramidite xe2x80x94Oxe2x80x94P(OR)-NR1R2 and phosphoramidate xe2x80x94Oxe2x80x94P(O)(OR)-NR1R2;
(c) sulphur groups such as xe2x80x94Oxe2x80x94S(O)(OH), xe2x80x94SH, xe2x80x94SR, xe2x80x94S(xe2x80x94O)xe2x80x94R, xe2x80x94S(O)2R, ROxe2x80x94S(O)2xe2x88x92, xe2x80x94Oxe2x80x94SO2NH2, xe2x80x94Oxe2x80x94SO2R1R2 or sulphamide xe2x80x94NHSO2NH2;
(d) amino groups such as xe2x80x94NHR, xe2x80x94NR1R2, xe2x80x94NHAc, xe2x80x94NHCOR, xe2x80x94NHxe2x80x94Oxe2x80x94COR, xe2x80x94NHSO3xe2x88x92, xe2x80x94NHSO2R, xe2x80x94N(SO2R)2, and/or amidino groups such as xe2x80x94NHxe2x80x94C(xe2x95x90NH)NH2 and/or ureido groups such as xe2x80x94NHxe2x80x94COxe2x80x94NR1R2 or thiouriedo groups such as xe2x80x94NHxe2x80x94C(S)xe2x80x94NH2;
(e) hydroxy groups and substituted hydroxy groups such as xe2x80x94OR3, where R3 is C1-10 unsubstituted or substituted alkyl, e.g. CHF2 or CF3, alkoxyalkyl, aryloxyalkyl, cycloalkyl, alkenyl (unsubstituted alkyl), alkylene (C3-7 cycloalkyl), xe2x80x94OCOR, aryl, heteroaryl, acetal, or where two hydroxyl groups are joined as a ketal;
(f) halogen substituents such as fluorine or chlorine;
(g) hydrogen, e.g. to provide a deoxy sugar;
wherein R, R1 and R2 are independently hydrogen or C1-10 unsubstituted or substituted alkyl or aryl;
with the proviso that the compound is not O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-ammonio-2-deoxy-xcex1-D-glucopyraiosyl)-(1xe2x86x926)-L-myo-inositol-1,2-cyclic phosphate and O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-L-myo-inositol.
In a further aspect the present invention provides a compound represented by the general formula:
Yxe2x80x94Xxe2x80x94xcex11,6-cyclitol
wherein,
X represents a sugar radical;
Y represents one to three sugar radicals;
the sugar radicals and cyclitol are individually unsubstituted or substituted with between one and four groups independently selected from:
(a) phosphoryl groups such as phosphate xe2x80x94Oxe2x80x94P(O)(OH)2; thiophosphate xe2x80x94Oxe2x80x94P(S)(OH)2; phosphate esters xe2x80x94Oxe2x80x94P(O)(OR)2; thiophosphate esters xe2x80x94Oxe2x80x94P(S)(OR)2; phosphonate xe2x80x94Oxe2x80x94P(O)OHR; thiophosphonate xe2x80x94Oxe2x80x94P(S)OHR; substituted phosphonate xe2x80x94Oxe2x80x94P(O)OR1R2; substituted thiophosphonate xe2x80x94Oxe2x80x94P(S)OR1R2; xe2x80x94Oxe2x80x94P(S)(OH)(SH); cyclic phosphate;
(b) other phosphorus containing compounds such as phosphoramidite xe2x80x94Oxe2x80x94P(OR)xe2x80x94NR1R2 and phosphoramidate xe2x80x94Oxe2x80x94P(O)(OR)xe2x80x94NR1R2;
(c) sulphur groups such as xe2x80x94Oxe2x80x94S(O)(OH), xe2x80x94SH, xe2x80x94SR, xe2x80x94S(xe2x80x94O)xe2x80x94R, xe2x80x94S(O)2R, ROxe2x80x94S(O)2xe2x88x92, xe2x80x94Oxe2x80x94SO2NH2, xe2x80x94Oxe2x80x94SO2R1R2 or sulphamide xe2x80x94NHSO2NH2;
(d) amino groups such as xe2x80x94NHR, xe2x80x94NR1R2, xe2x80x94NHAc, xe2x80x94NHCOR, xe2x80x94NHxe2x80x94Oxe2x80x94COR, xe2x80x94NHSO3xe2x88x92, xe2x80x94NHSO2R, xe2x80x94N(SO2R)2, and/or amidino groups such as xe2x80x94NHxe2x80x94C(xe2x95x90NH)NH2 and/or ureido groups such as xe2x80x94NHxe2x80x94COxe2x80x94NR1R2 or thiouriedo groups such as xe2x80x94NHxe2x80x94C(S)xe2x80x94NH2;
(e) hydroxy groups and substituted hydroxy groups such as xe2x80x94OR3, where R3 is C1-10 unsubstituted or substituted alkyl, e.g. CHF2 or CF3, alkoxyalkyl, aryloxyalkyl, cycloalkyl, alkenyl (unsubstituted alkyl), alkylene (C3-7 cycloalkyl), xe2x80x94OCOR, aryl, heteroaryl, acetal, or where two hydroxyl groups are joined as a ketal;
(f) halogen substituents such as fluorine or chlorine,
(g) hydrogen, e.g. to provide a deoxy sugar;
wherein R, R1 and R2 are independently hydrogen or C1-10 unsubstituted or substituted alkyl or aryl;
with the proviso that the compound is not O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-ammonio-2-deoxy-xcex1-D-glucopyranosyl)-(1xe2x86x9216)-L-myo-inositol-1,2-cyclic phosphate and O-(6-hydrogenphosphonate-xcex1-D-mannopyranosyl)-(1xe2x86x924)-(2-amino-2-deoxy-xcex1-D-glucopyranosyl)-L-myo-inositol.
The compounds may be provided as racemic or diasteromeric mixtures, resolved or partially resolved optical isomers, and as pharmaceutically acceptable salts, esters and derivatives as discussed in more detail below.
Examples of compounds within this embodiment of the invention are RGL1014, RGL1021, RGL1022, RGL1105 and compounds 19 and 25.
Preferably, the X or Y sugar residue is a hexose or a pentose, and may be an aldose or a ketose. The sugar residue can a member of the D or L series and can include amino sugars, deoxy sugars and their uronic acid derivatives. Preferably, where the sugar residue is a hexose, it is selected from the group consisting of glucose, galactose or mannose, or substituted hexose sugar residues such as an amino sugar residue such as hexosamine, galactosamine or glucosamine, and more preferably D-glucosamine (2-amino-2-deoxy-D-glucose) or D-galactosamine (2-amino-2-deoxy-D-galactose). Preferred pentose sugar residues include arabinose, fucose and ribose. The X or Y sugar residue is optionally substituted at one, two, three or four positions, other than the anomeric position or the position of linkage of the other radical or to the cyclitol.
The cyclitol moiety is preferably selected from myo-inositol, chiro-inositol or pinitol (3-O-methyl-chiro-inositol), in either their D or L forms, and is optionally substituted at one or more of the positions other than the position of linkage to the sugar radical, or in the case of pinitol additionally the 3-position. The sugar radical is optionally substituted at one, two, three or four positions other than at the position of linkage to the inositol moiety (the anomeric position). Where the cyclitol moiety is substituted at the 3-position (e.g is a pinitol or a related compound), preferably the substituent is C1-10 alkyl, and may be a substituted or unsubstituted primary, secondary or tertiary alkyl group. Examples of substituted groups include CF3, X(CH2)nxe2x80x94Oxe2x80x94 (where X is hydrogen, or substituted or unsubstituted alkyl), CHF2Oxe2x80x94. A preferred alkyl group is methyl when the cyclitol is D or L-pinitol (3-O-methyl-chiro-inositol), and is optionally substituted at one or more of the positions other than the 3-position or the position of linkage to the sugar residue. In further embodiments, the cyclitol may have one or more of the hydroxyl groups through which the substituents described above are removed so that any substituent(s) are linked to the ring carbon atom. The sugar residue is optionally substituted at one, two, three, or four positions other than at the position of linkage to the inositol moiety.
Preferably the X and Y sugar residues are linked to each other via a 1,1 linkage, 1,2 linkage, 1,3 linkage, 1,4 linkage or 1,6 linkage. The linkage between the units may be an xcex1 or xcex2 linkage. The linkage of the X sugar residue to the cyclitol is generally a 1,6 linkage via one of the oxygen atoms of the cyclitol moiety. However, this oxygen atom can be replaced one or more times by xe2x80x94CH2xe2x80x94 or xe2x80x94Sxe2x80x94 groups.
In preferred embodiments, the present invention provides a compound, or a substituted form thereof as defined above, selected from the group consisting of:
RGL1014 O-(D-galactopyranosyl)-xcex1(1,4)-O-(2xe2x80x2-amino-2xe2x80x2-deoxy-D-glucanopyranosyl)-xcex1(1,6)-myo-inositol.
RGL1021 O-(D-galactopyranosyl)-xcex1(1,4)-O-(2xe2x80x2-amino-2xe2x80x2-deoxy-D-glucanopyranosyl)-xcex1(1,6)-chiro-inositol.
RGL1022 O-(D-galactopyranosyl)-xcex1(1,4)-O-(2xe2x80x2-amino-2xe2x80x2-deoxy-D-glucanopyranosyl)-xcex1(1,6)-chiro-inositol-1-phosphate.
RGL1105 1xe2x80x3-D-4xe2x80x2-O-(6xe2x80x3-phosphate-xcex1-D-mannopyranosyl)-[1xe2x80x2-D-6-O-(2xe2x80x2-amino-2xe2x80x2-deoxy-xcex1-D-glucopyranosyl)-myo-inositol].
Compound 25 O-xcex1-D-Mannopyranosyl-(1-2)-O-xcex1-D-mannopyranosyl-(1-6)-O-xcex1-D-mannopyranosyl-(1-4)-O-2-ammonio-2-deoxy-xcex1-D-glucopyranosyl-(1-6)-D-chiro-inositol-1-phosphate.
Compound 19 O-xcex2-D-galactopyranosyl-(1-4)-2-ammonio-2-deoxy-xcex1-D-galactopyranosyl-(1-6)-D-chiro-inositol-1-phosphate.
In a further aspect, the present invention provides methods for making the compounds of the invention or their intermediates as set out in the following experimental description and the schemes. In a further related aspect, the present invention further relates to compounds which are the novel intermediates described herein.
In a further aspect, the present invention provides one or more of the above compounds for use in a method of medical treatment. The compounds may be useful as IPG mimetics or IPG antagonists, e.g. competitive antagonists.
In a further aspect, the present invention provides the use of one or more of the above compounds for the preparation of a medicament for the treatment of a condition ameliorated by the administration of an inositol phosphoglycan (IPG) second messenger or an IPG antagonist. Examples of such conditions are set out in the pharmaceutical uses section below.
In a further aspect, the present invention provides a method of treating a condition in a mammal ameliorated by an inositol phosphoglycan (IPG) second messenger or an IPG antagonist, the method comprising administering to the mammal a therapeutically effective amount of one or more of the above compounds.
Embodiments of the invention will now be described by way of example and not limitation with reference to the accompanying drawings.
Scheme 1 shows the synthesis of compound 4.
Scheme 2 shows the synthesis of RGL1021 from compound 4.
Scheme 3 shows the production of RGL1022 from compound 7.
Scheme 4 shows the production of compound 19, a derivative of compound 4.
Schemes 5(I) and 5(II) show the synthesis of compound 25.
Scheme 6 shows the preparation of trisaccharide 28 (RGL 1014).
Scheme 7 shows the preparation of compound RGL1105.
Inositol Phosphoglycans (IPGs)
IPG-A mediators modulate the activity of a number of insulin-dependent enzymes such as cAMP dependent protein kinase (inhibits), adenylate cyclase (inhibits) and cAMP phospho-diesterases (stimulates). In contrast, IPG-P mediators modulate the activity of insulin-dependent enzymes such as pyruvate dehydrogenase phosphatase (stimulates) and glycogen synthase phosphatase (stimulates). The A-type mediators mimic the lipogenic activity of insulin on adipocytes, whereas the P-type mediators mimic the glycogenic activity of insulin on muscle. Both A-and P-type mediators are mitogenic when added to fibroblasts in serum free media. The ability of the mediators to stimulate fibroblast proliferation is enhanced if the cells are transfected with the EGF-receptor. A-type mediators can stimulate cell proliferation in the chick cochleovestibular ganglia.
Soluble IPG fractions having A-type and P-type activity have been obtained from a variety of animal tissues including rat tissues (liver, kidney, muscle, brain, adipose, heart) and bovine liver. IPG-A and IPG-P biological activity has also been detected in human liver and placenta, malaria parasitized RBC and mycobacteria. The ability of an anti-inositolglycan antibody to inhibit insulin action on human placental cytotrophoblasts and BC3H1 myocytes or bovine-derived IPG action on rat diaphragm and chick cochleovestibular ganglia suggests cross-species conservation of many structural features. However, it is important to note that although the prior art includes these reports of IPG-A and IPG-P activity in some biological fractions, the purification or characterisation of the agents responsible for the activity is not disclosed.
IPG-A substances are cyclitol-containing carbohydrates, also containing Zn2+ ions and phosphate and having the properties of regulating lipogenic activity and inhibiting cAMP dependent protein kinase. They may also inhibit adenylate cyclase, be mitogenic when added to EGF-transfected fibroblasts in serum free medium, and stimulate lipogenesis in adipocytes.
IPG-P substances are cyclitol-containing carbohydrates, also containing Mn2+ and/or Zn2+ ions and phosphate and having the properties of regulating glycogen metabolism and activating pyruvate dehydrogenase phosphatase. They may also stimulate the activity of glycogen synthase phosphatase, be mitogenic when added to fibroblasts in serum free medium, and stimulate pyruvate dehydrogenase phosphatase.
Methods for obtaining A-type and P-type mediators are set out in Caro et al, 1997, and in WO98/11116 and WO98/11117. Protocols for determining characteristic IPG biological activities such as PDH activation, PKA inhibition, acetylCoA activation, fructose-1,6-bis-phosphatase activity and lipogenesis are well known in the art, e.g. as described in Caro et al [14].
DRUG FORMULATION
The compounds of the invention may be derivatised in various ways. As used herein xe2x80x9cderivativesxe2x80x9d of the compounds includes salts, coordination complexes with metal ions such as Mn2+ and Zn2+, esters such as in vivo hydrolysable esters, free acids or bases, hydrates, prodrugs or lipids, coupling partners.
Salts of the compounds of the invention are preferably physiologically well tolerated and non toxic. Many examples of salts are known to those skilled in the art. Compounds having acidic groups, such as phosphates or sulfates, can form salts with alkaline or alkaline earth metals such as Na, K, Mg and Ca, and with organic amines such as triethylamine and Tris(2-hydroxyethyl)amine. Salts can be formed between compounds with basic groups, e.g. amines, with inorganic acids such as hydrochloric acid, phosphoric acid or sulfuric acid, or organic acids such as acetic acid, citric acid, benzoic acid, fumaric acid, or tartaric acid. Compounds having both acidic and basic groups can form internal salts.
Esters can be formed between hydroxyl or carboxylic acid groups present in the compound and an appropriate carboxylic acid or alcohol reaction partner, using techniques well known in the art.
Derivatives which as prodrugs of the compounds are convertible in vivo or in vitro into one of the parent compounds. Typically, at least one of the biological activities of compound will be reduced in the prodrug form of the compound, and can be activated by conversion of the prodrug to release the compound or a metabolite of it. An example of prodrugs are glycolipid derivatives in which one or more lipid moieties are provided as substituents on the sugar residue or the cyclitol moieties, leading to the release of the free form of the compound by cleavage with a phospholipase enzyme. Examples of prodrugs include the use of protecting groups which may be removed in situ releasing active compound or serve to inhibit clearance of the drug in vivo. Protecting groups are well known in the art and are discussed further below. An example of a suitable protecting group that might be used as a prodrug is the azido group used in the synthesis below, e.g. on the 2-position of the sugar moiety.
Other derivatives include coupling partners of the compounds in which the compounds is linked to a coupling partner, e.g. by being chemically coupled to the compound or physically associated with it. Examples of coupling partners include a label or reporter molecule, a supporting substrate, a carrier or transport molecule, an effector, a drug, an antibody or an inhibitor. Coupling partners can be covalently linked to compounds of the invention via an appropriate functional group on the compound such as a hydroxyl group, a carboxyl group or an amino group. Other derivatives include formuulating the compounds with liposomes.
Pharmaceutical Compositions
The compounds described herein or their derivatives can be formulated in pharmaceutical compositions, and administered to patients in a variety of forms, in particular to treat conditions which are ameliorated by the administration of inositol phosphoglycan second messengers or IPG antagonists such as competitive antagonist.
Pharmaceutical compositions for oral administration may be in tablet, capsule, powder or liquid form. A tablet may include a solid carrier such as gelatin or an adjuvant or an inert diluent. Liquid pharmaceutical compositions generally include a liquid carrier such as water, petroleum, animal or vegetable oils, mineral oil or synthetic oil. Physiological saline solution, or glycols such as ethylene glycol, propylene glycol or polyethylene glycol may be included. Such compositions and preparations generally contain at least 0.1 wt % of the compound.
Parental administration includes administration by the following routes: intravenous, cutaneous or subcutaneous, nasal, intramuscular, intraocular, transepithelial, intraperitoneal and topical (including dermal, ocular, rectal, nasal, inhalation and aerosol), and rectal systemic routes. For intravenous, cutaneous or subcutaneous injection, or injection at the site of affliction, the active ingredient will be in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability. Those of relevant skill in the art are well able to prepare suitable solutions using, for example, solutions of the compounds or a derivative thereof, e.g. in physiological saline, a dispersion prepared with glycerol, liquid polyethylene glycol or oils.
In addition to one or more of the compounds, optionally in combination with other active ingredient, the compositions can comprise one or more of a pharmaceutically acceptable excipient, carrier, buffer, stabiliser, isotonicizing agent, preservative or anti-oxidant or other materials well known to those skilled in the an. Such materials should be non-toxic and should not interfere with the efficacy of the active ingredient. The precise nature of the carrier or other material may depend on the route of administration, e.g. orally or parentally.
Liquid pharmaceutical compositions are typically formulated to have a pH between about 3.0 and 9.0, more preferably between about 4.5 and 8.5 and still more preferably between about 5.0 and 8.0. The pH of a composition can be maintained by the use of a buffer such as acetate, citrate, phosphate, succinate, Tris or histidine, typically employed in the range from about 1 mM to 50 mM. The pH of compositions can otherwise be adjusted by using physiologically acceptable acids or bases.
Preservatives are generally included in pharmaceutical compositions to retard microbial growth, extending the shelf life of the compositions and allowing multiple use packaging. Examples of preservatives include phenol, meta-cresol, benzyl alcohol, para-hydroxybenzoic acid and its esters, methyl paraben, propyl paraben, benzalconium chloride and benzethonium chloride. Preservatives are typically employed in the range of about 0.1 to 1.0% (w/v).
Preferably, the pharmaceutically compositions are given to an individual in a xe2x80x9cprophylactically effective amountxe2x80x9d or a xe2x80x9ctherapeutically effective amountxe2x80x9d (as the case may be, although prophylaxis may be considered therapy), this being sufficient to show benefit to the individual. Typically, this will be to cause a therapeutically useful activity providing benefit to the individual. The actual amount of the compounds administered, and rate and time-course of administration, will depend on the nature and severity of the condition being treated. Prescription of treatment, e.g decisions on dosage etc, is within the responsibility of general practitioners and other medical doctors, and typically takes account of the disorder to be treated, the condition of the individual patient, the site of delivery, the method of administration and other factors known to practitioners. Examples of the techniques and protocols mentioned above can be found in Remington""s Pharmaceutical Sciences, 16th edition, Osol, A. (ed), 1980. By way of example, and the compositions are preferably administered to patients in dosages of between about 0.01 and 100 mg of active compound per kg of body weight, and more preferably between about 0.5 and 10 mg/kg of body weight.
The composition may further comprise one or more other pharmaceutically active agents, either further compounds of the invention, inositol phosphoglycans, growth factors such as insulin, NGF or other growth factors listed below, or other drugs, e.g. those in use for the treatment of diabetes or other conditions set out below.
Medical Uses
As set out above, IPGs are second messengers for a range of different growth factors, including insulin, nerve growth factor, hepatocyte growth factor, insulin-like growth factor I (IGF-I), fibroblast growth factor, transforming growth factor xcex2, the action of IL-2 on B-cells and T-cells, ACTH signalling of adrenocortical cells, IgE, FSH and hCG stimulation of granulosa cells, thyrotropin stimulation of thyroid cells, cell proliferation in the early developing ear and rat mammary gland. Consequently, IPGs or their antagonists can be used in the treatment or amelioration of disorders mediated by the growth factors or to mimic specific growth factor biological activities.
Examples of conditions which can be treated using IPGs or IPG antagonists include, diabetes, obesity, pre-eclampsia, neurotrophic disorders, hepatic damage and adrenal atrophy.
WO98/10791 discloses that pre-eclampsia is characterised by elevated levels of IPG-P and that it can be treated using an IPG-P antagonist. Compounds of the invention which are IPG-P antagonists, e.g. antagonists which compete with wild-type IPG-P but lack one or more of its activities, could be used in the treatment of pre-eclampsia.
The use of both IPG-P and IPG-A and IPG-A antagonists in the diagnosis and treatment of diabetes is disclosed in WO98/11435. This application discloses that in some forms of diabetes the ratio of P:A-type IPGs is imbalanced and can be corrected by administering a medicament containing an appropriate ratio of IPG-P, IPG-A or antagonist(s) thereof. In particular, it describes the treatment of obese type II diabetes (NIDDM) patients with a P-type IPG and/or an A-type IPG antagonist and the treatment of IDDM or lean type II diabetes (body mass index  less than 27) with a mixture of P- and A-type IPGs, typically in a P:A ratio of about 6:1 for males and 4:1 for females. The compounds and compositions of the present invention can be employed in such types of treatment. More particularly, the compounds are likely to be of use in the treatment of various form of diabetes and diabetic complications including diabetes due to insulin resistance, insulin resistance in type I diabetes and brittle diabetes, obese or lean type II diabetes, and of conditions associated with insulin resistance or insulin underproduction, such as neurotrophic disorders or polycystic ovary syndrome, lipodystrophy, age-related memory loss, and post-ischaemic damage secondary to stroke or post-transplant complications.
The compounds of this invention are also likely to be of use in controlling neuron proliferation or neurite outgrowth, either in vitro or in vivo, e.g. acting as a nerve or neurite growth factor mimetic second messenger. They may thus have applications in the treatment and/or diagnosis of any condition related to neuron proliferation or neurite differentiation. WO99/38516 discloses that IPG-A and synthetic mimetics thereof cause neuron proliferation, mimicking the action of the growth factor IGF-I. In contrast, IPG-P and synthetic mimetics thereof such as compound C4 cause neurite outgrowth. The neurons may be central (brain and spinal cord) neurons, peripheral (sympathetic, parasympathetic, sensory and enteric) neurons, or motor neurons.
Treatments may involve the treatment of damage to nerve, spinal cord or central nervous system damage secondary to trauma, or autoimmune or metabolic damage, or post-ischaemic damage secondary to stroke or post-transplant complications, motor neuron disease, neurodegenerative disorders or neuropathy. Damage to the nervous system includes the results of trauma, stroke, surgery, infection (e.g. by viral agents), ischemia, metabolic disease, toxic agents, or a combination of these or similar causes. Motor neuron disease includes conditions involving spinal muscular atrophy, paralysis or amyotrophic lateral sclerosis. Neurodegenerative disorders include Parkinson""s disease, Alzheimer""s disease, epilepsy, multiple sclerosis, Huntingdon""s chorea and Meniere""s disease.
The compounds of the invention may also be usefull as hepatocyte growth factor mimetic second messengers, e.g. in the preparation of medicaments for the treatment of hepatic damage caused by infection, alcohol abuse, drug sensitivity, or autoimmunity. The compounds may also be useful as fibroblast growth factor mimetic second messengers or epidermal growth factor mimetic second messengers, e.g. in the preparation of medicaments for the promotion of wound healing following surgery or trauma or tissue damage induced by ischaemia or autoimmunity.
In other embodiments, the compounds of the invention may be useful as adrenal cell growth factor mimetic second messengers or ACTH mimetic second messengers in the preparation of a medicament for the treatment of disease states involving adrenal atrophy.
Methods of Making the Compounds
Based on the disclosure herein, the knowledge in the art and in references [3-11], the skilled person could couple sugar residues and cyclitols together, optionally with one or more substituents.
Useful guidance on the synthesis of the exemplified compounds and for introducing the substituents set out herein is provided by the papers by Gigg and Gigg, Khiar and Martin-Lomas [5] and Baeschlin et al [18] and the references cited therein,
Phosphoryl groups such as phosphate, cyclic phosphate or substituted phosphate or cyclic phosphate can be substituted into the compounds of the invention by the phosphate or phosphoramidite method, Bannwath et al, Helvetica Chemica Acta, 70:175-186, 1987 and Yu and Fraser-Reid, Tetrahedron Lett., 29:979-982, 1988.
Phosphate protecting groups can also be synthesized according to the methods disclosed in Hoeben-Weyl, Methods of Organic Chemistry, volume 12/1 or 12/2, Teilheimer, Synthetic Methods of Organic Chemistry, Vol 45. Protecting groups for the OH of sugars include menthoxycarbonyl (MntCO), acetal (in particular, two R groups may together represent a bridging acetal such as O-cyclohexylidene, O-isopropylidene or O-benzylidene), tert-butyldimethylsilyl (TBDMS), benzyl (Bn), tert-butyldiphenylsilyl (TBDPS). Many protecting groups suitable for use in the syntheses and reactions of saccharides are known and are well documented in standard reference works. The choice depends in part on the route by which the compound is synthesised and/or on the uses to which it is to be put, including the reactions which it is subsequently intended to undergo.
Bioactivity Assays
The compounds of the invention can be tested for one or more the characteristic IPGP and/or IPG-A activities mentioned above to determine whether they will be suitable for use a IPG mimetics or antagonists. Preferred assays measure the effect of the compounds on PDH phosphatasc, PKA or lipogenesis. Protocols for these assays are provided in Caro et al [14].